This invention relates to an exhaust cooling device for small sized boat engines and more particularly to an improved arrangement for cooling the exhaust system of an internal combustion engine.
It is well known that the exhaust system of an internal combustion engine generates a large amount of heat. For this reason, it is the practice in many applications, to cool the exhaust system and particularly the exhaust pipes through which the exhaust gases pass. Doing so is particularly important in marine applications and various arrangements have been proposed for cooling the exhaust gases in such applications. Most of the cooling systems for marine exhausts utilize the cooling water from the engine which is returned to the body of water in which the watercraft is operated. Frequently, the cooling water is discharged into the exhaust system so as to assist in cooling the exhaust. This is particularly important in connection with watercraft since they frequently use elastic joints in the exhaust system so as to reduce vibration. If the exhaust joints are not adequately cooled, the elastic material may deteriorate and eventually fail.
Another way in which the exhaust system or components are cooled is by forming a cooling jacket around portions of the exhaust pipe. This cooling jacket is supplied with coolant from the engine cooling jacket and this water is then discharged back into the body of water in which the watercraft is operating. Although this method of cooling the exhaust pipes is very helpful, when the engine is running at low speeds there is very little coolant flow through the engine cooling jacket. As a result, the cooling jacket encircling the exhaust pipe may not be fully filled with coolant and, in fact, under extreme cases the coolant may not even touch the exhaust pipe. As a result, overheating can occur.
It is, therefore, a principle object of this invention to provide an improved cooling arrangement for an exhaust pipe for an internal combustion engine.
It is a further object of this invention to provide the cooling arrangement for an exhaust pipe wherein it is insured that the exhaust pipe is encircled with coolant at all times when the engine is running.
It is a further object of this invention to provide an improved cooling system for the exhaust of a small watercraft.